An equiconvex lens of radius of curvature R = | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) For an equiconvex lens,the power of the lens is given by $P_L = (\mu - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right)$.Given $R_1 = 20 \, cm$ and

Vedclass · Accepted Answer

$5$

Vedclass · Answer

(B) For an equiconvex lens,the power of the lens is given by $P_L = (\mu - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} ight)$.Given $R_1 = 20 \, cm$ and $R_2 = -20 \, cm$,and $\mu = 1.5$:$P_L = (1.5 - 1) \left( \frac{1}{20} - \frac{1}{-20} ight) = 0.5 	imes \left( \frac{2}{20} ight) = 0.5 	imes 0.1 = 0.05 \, cm^{-1} = 5 \, D$.When one side is silvered,the system acts as a mirror with power $P_{eq} = 2P_L + P_m$.The power of the mirror $P_m$ formed by the silvered surface is $P_m = -\frac{1}{f_m} = -\frac{1}{R/2} = -\frac{2}{R}$.Since the light reflects from the concave side of the silvered surface,$R = -20 \, cm$,so $P_m = -\frac{2}{-20} = 0.1 \, cm^{-1} = 10 \, D$.The total power is $P_{eq} = 2(5) + 10 = 20 \, D$.The equivalent focal length is $f_{eq} = -\frac{1}{P_{eq}} = -\frac{1}{20} \, m = -5 \, cm$.

An equiconvex lens of radius of curvature $R = 20 \, cm$ and refractive index $\mu = 1.5$ is silvered on one side. The equivalent focal length of the system is: (in $, cm$)

Similar Questions

When the plane surface of a plano-convex lens is silvered,it behaves as a concave mirror of focal length $60 \ cm$. However,when the convex surface is silvered,it behaves as a concave mirror of focal length $20 \ cm$. What is the refractive index of the lens?

$A$ plano-convex lens $(f = 20 \ cm)$ is silvered at the plane surface. Now,the new focal length $F$ will be........$cm$.

$A$ point-like object is placed at a distance of $1\, m$ in front of a convex lens of focal length $0.5\, m$. $A$ plane mirror is placed at a distance of $2\, m$ behind the lens. Find the position and nature of the final image formed by the system.

When a thin convex lens is placed in contact with a concave mirror of the same focal length,the resultant focal length of the system is ......

Vedclass Test Series

Exam Paper Generator

Online Exam Module